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Woo, On Ting. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 102-121). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.vi / List of Figures --- p.ix / List of Plates --- p.xiv / List of Tables --- p.xv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- General characteristics --- p.1 / Chapter 1.2 --- Sources of PAHs --- p.6 / Chapter 1.3 --- Adsorption of PAHs --- p.7 / Chapter 1.4 --- Environmental fate of PAHs --- p.9 / Chapter 1.4.1 --- Transformation --- p.10 / Chapter 1.4.1.1 --- PAHs in atmosphere --- p.10 / Chapter 1.4.1.2 --- PAHs in water --- p.11 / Chapter 1.4.1.3 --- PAHs in soil and sediment --- p.12 / Chapter 1.4.2 --- Route of entry into human --- p.13 / Chapter 1.5 --- Toxicity of PAHs on human --- p.14 / Chapter 1.5.1 --- Cancer --- p.14 / Chapter 1.5.2 --- Other health effects - acute effects --- p.16 / Chapter 1.5.3 --- Other health effects - chronic effects --- p.16 / Chapter 1.5.3.1 --- Respiratory effect --- p.16 / Chapter 1.5.3.2 --- Dermal effect --- p.17 / Chapter 1.6 --- Treatment methods of PAHs --- p.17 / Chapter 1.6.1 --- Incineration --- p.17 / Chapter 1.6.2 --- Bioremediation --- p.18 / Chapter 1.6.3 --- Chemical oxidation --- p.19 / Chapter 1.6.4 --- Combined biological-chemical treatment --- p.22 / Chapter 1.6.5 --- Advanced oxidation processes --- p.23 / Chapter 1.6.5.1 --- Photocatalytic oxidation --- p.24 / Chapter 1.6.5.2 --- Operation parameters of PCO --- p.26 / Chapter 1.7 --- PAH contamination in Hong Kong --- p.27 / Chapter 2 --- Objectives --- p.28 / Chapter 3 --- Materials and methods --- p.29 / Chapter 3.1 --- Chemicals --- p.29 / Chapter 3.2 --- Photocatalytic reactor --- p.30 / Chapter 3.3 --- Ultrasonic extraction of PAHs --- p.32 / Chapter 3.4 --- Quantification of PAHs --- p.32 / Chapter 3.5 --- Photocatalytic reactivity of PAHs --- p.34 / Chapter 3.6 --- The effect of acetone on performance of PCO --- p.35 / Chapter 3.7 --- Identification of intermediates of PAHs --- p.36 / Chapter 3.8 --- Toxicity test --- p.38 / Chapter 3.9 --- Study of mixture effect --- p.40 / Chapter 4 --- Results and discussion --- p.42 / Chapter 4.1 --- Quantification of PAHs --- p.42 / Chapter 4.2 --- Extraction efficiency of PAHs --- p.42 / Chapter 4.3 --- Photocatalytic reactivity of PAHs --- p.44 / Chapter 4.4 --- The effect of acetone on performance of PCO --- p.52 / Chapter 4.5 --- Identification of intermediates --- p.62 / Chapter 4.5.1 --- PCO degradation of naphthalene --- p.62 / Chapter 4.5.2 --- PCO degradation of acenaphthylene --- p.66 / Chapter 4.5.3 --- PCO degradation of phenanthrene --- p.69 / Chapter 4.5.4 --- PCO degradation of anthracene --- p.72 / Chapter 4.5.5 --- PCO degradation of benzo[a]anthracene --- p.75 / Chapter 4.5.6 --- PCO degradation of pyrene --- p.78 / Chapter 4.6 --- Toxicity test --- p.80 / Chapter 4.7 --- Study of mixture effect --- p.87 / Chapter 5 --- Conclusions --- p.99 / Chapter 6 --- References --- p.102 / Chapter 7 --- Appendices --- p.122

Sedimentary organic matter contains many compounds that have no obvious biogenic precursors, so their formation and occurrence are of geochemical interest. The first part of this thesis (chapters 2-5) discusses the results obtained from studying hydrocarbon racemates. Some of the compounds identified are also suggested as intermediates in the formation of alkylnaphthalenes identified in chapters 6-7. The second part of this thesis (chapters 6-11) covers the identification of a range of alkylnaphthalenes and alkylphenanthrenes in sedimentary organic matter. Possible pathways for the formation of these hydrocarbons are outlined and their application as probes into the processes of petroleum formation are described.In chapter 2 the use of permethylated cyclodextrin capillary gas chromatography columns to separate hydrocarbon racemates are reported. Chapter 3 reports the synthesis of 1,2,2,5-tetramethyltetralin and 1,2,2,5,6-pentamethyltetralin and identifies them as racemates in crude oil. They are proposed as intermediates in the formation of sedimentary alkylnaphthalenes (identified in chapters 6 and 7).The identification of isodihydro-ar-curcumene in sedimentary organic matter is described in chapters 4 and 5. It co-occurs in crude oil with dihydro-ar-curcumene and is suggested to originate from this compound via a sedimentary rearrangement process. Chiral GC-MS techniques have been used to show the presence of both enantiomers of these compounds in crude oils. The elution order of the enantiomers has been established using reference compounds of known configuration. The effects of maturity and biodegradation on dihydro-ar-curcumene and isodihydro-ar-curcumene enantiomers is reported. Optically pure dihydro-ar-curcumene from natural products undergoes rapid racemisation in the subsurface, yielding a racemic mixture before the onset of significant oil formation. ++ / 1,2-Alkyl shifts on the aromatic ring also begin at an early stage to yield isodihydro-ar-curcumene and these processes continue with increasing maturity. Laboratory experiments using proton and clay catalysts (Lewis acid catalyst) show that the alkyl shift reaction is catalysed by both proton and Lewis acids, and racemisation is only catalysed by Lewis acids. A moderately biodegraded crude oil has been shown to be depleted in the R enantiomer of dihydro-ar-curcumene and an extensively degraded oil has dihydro-ar-curcumene depleted relative to isodihydro-ar-curcumene.The identification of a number alkylnaphthalenes and their possible origins in sedimentary organic matter is described in chapters 6 and 7. In chapter 6 a previously unreported tetramethylnaphthalene (TeMN) was identified in petroleum. This compound is structurally similar to bicyclic compounds of microbial origin and these are suggested as a likely source, via a tetralin intermediate identified in chapter 3. In chapter 7 isomeric pentamethylnaphthalenes previously unreported in sedimentary organic matter are reported. These isomeric pentamethylnaphthalenes (PMNs) were identified in a number of crude oils and sediments, ranging in age from Proterozoic to Tertiary. 1,2,3,5,6-PMN is suggested to form predominantly from the aromatisation of drimanoid precursors via 1,2,2,5,6-pentamethyltetralin identified in chapter 3. In laboratory experiments, the other pentamethylnaphthalenes were generated from 1,2,3,5,6-PMN in proportions that reflect the relative stability of the isomers. By analogy, the other PMNs in sediments are suggested to arise via acid catalysed isomerisation or transalkylation processes. A maturity parameter was developed based on laboratory experiments in conjunction with observed distributions of pentamethylnaphthalenes.The formation of alkylnaphthalenes and alkylphenanthrenes through a ++ / methylation process is discussed in chapters 8-10. Several crude oils and shales which contain anomalously high concentrations of 1,6-dimethylnaphthalene, 1,2,5-trimethylnaphthalene, 1,2,7-trimethylnaphthalene, 1,2,3,5-tetramethylnaphthalene, 1,2,3,5,6-pentamethylnaphthalene, 2-methyl-6-isopropyl-1(4-methylpentyl)naphthalene, phenanthrene, 1-methylphenanthrene, 1,7-dimethylphenanthrene and retene have been shown to contain relatively high concentrations of their corresponding methylated counterparts. In laboratory experiments carried out under mild conditions, each of the alkylnaphthalenes and alkylphenanthrenes have been shown to be methylated in specific positions when heated with a methyl donor in the presence of a clay catalyst. These observations have been interpreted as evidence for a sedimentary methylation process.The effect of biodegradation on alkylnaphthalenes and alkylphenanthrenes formed from sedimentary methylation is described in chapter 11. Land-plant-derived aromatic hydrocarbons with a range of susceptibilities to reservoir biodegradation have been identified in crude oils. These compounds are the result of reactions of natural products involving aromatisation, rearrangement and methylation in the sediments (chapters 9 and 10). They are therefore suggested as markers for land-plants in severely biodegraded oils in which most of the other biologically derived compounds cannot be recognised. The order of biodegradability of these compounds has been assessed relative to their non-methylated counterparts namely 6-isopropyl-2-methyl-1-(4-methylpentyl)naphthalene and retene. The order of degradation of the four compounds is : retene < 9-methylretene ~ 6-isopropyl-2-methyl-1-(4-methylpentyl)naphthalene > 6-isopropyl-2,4-dimethyl-1-(4-methylpentyl)naphthalene. These results have been used to assess that a crude oil is a mixture of severely biodegraded and ++ / less biodegraded crude oil.

A series of tri-substituted iron and cobalt complexes of the form [M(A)3]n+ were synthesized, and were characterised by UV/Visible absorption and 1H-NMR spectroscopy. The complexes [Co(phen)2(en)]3+ and [Co(bipy)2(en)]3+ have been reported in the literature but 1H-NMR spectroscopy showed that the material produced in both syntheses is [Co(en)3]3+. Spectroscopy further showed that these species cannot be prepared by the literature methods. The complexes were tested in the oxidation of adamantane in the solvents, acetic acid and trifluoroacetic acid and they all oxidised adamantane to a mixture of 1-adamantanol, 1-adamantanol and 2-adamantanone both in the presence and the absence of the oxidant, O2. In all the reactions, however, the yield of conversion was very low. The mechanism for this oxidation was different depending on the presence or absence of O2. In the presence of O2 a catalytic cycle was produced for the oxidation of adamantine. In the oxidation in the presence and absence of O2 there was little variation in activity between the tri-substituted iron and cobalt complexes of 1,10-phenanthroline when compared with the analgous 2,2’-bipyridine complexes. However, the substitution of an ethylenediamine ligand into the co-ordination sphere of cobalt produced significant increase in the activity, although the change was not constant. / Master of Science (Hons)

Dry/CO2 reforming is one the hydrocarbon processes that recently has been interesting due to it is ability of producing a lower synthesis gas ratio (H2/CO). This synthesis gas is a highly significant product since it costs more than 50% of the total capital cost of gas to liquid (GTL) process. However, since this reaction is thermodynamically limited, higher temperature or lower pressure is required to achieve higher conversion. Typically, reaction temperatures between 1073 and 1173 K are used for catalytic dry reforming reactions. Consequently, these extreme temperatures lead to a severe carbon deposition causing a catalyst deactivation which is the major difficulty related to CO2 reforming reaction. This has pushed the efforts to be focused mainly on the development of new catalysts. In fact, dry reforming of propane is an equilibrium-limited reaction which can be shifted to the product side by removing one of the products out of the system which can be achieved using a selective membrane reactor. This research is dedicated to investigate and study the catalytic performance of dry reforming of propane over cobalt-nickel catalyst under the temperature range of 773-973 K. This bimetallic catalyst supported on ??-Al2O3 has been utilized in this research since it exhibits better activity, selectivity, and deactivation resistance than monometallic catalysts. Based on this, the primary aims of this thesis are to examine this catalyst and to study the impact of using membrane reactor. In addition, the reaction mechanism and kinetic are investigated using a fixed-bed reactor. Experimental observations have exposed that the catalyst is offering good results under this reaction. The catalysts analysis has confirmed the presence of metal oxides in the catalyst. However, only at a lower carbon dioxide to propane ratio, i.e. lower than 3.5, a carbon signal has been reported. The activation energy study indicates that the process is unlimited by diffusion. The reaction order for propane and carbon dioxide has been found to be zero and 1.17 respectively. This in turn has indicated that C3H8 activation reaction is taking place rapidly and carbon dioxide is suggested to be involved in the rate determining step. In membrane reactor operation, the production rates for H2 and CO have been reported to increase as the sweep gas flow rate increases. The co-current mode offers higher production rate and more stability than counter-current mode over the range of feed ratio. On the other hand, fixed bed reactor shows stable performance and produces more CO and H2 for both modes.

This study involves the use of ball mill as a mechanochemical reactor in the destruction of environmental contaminants. Although the technology has the potential to be used for a wide range of organic contaminants, this study focused on polycyclic aromatic hydrocarbons (PAH's) and aliphatic hydrocarbons. There are different methods for the remediation of the environmental contaminants such as biological, chemical and thermal techniques, most of which are costly. The ball mill is less costly as it involves low technology and little or no other chemicals seem to be needed to give complete destruction of the substances investigated. The mill is relatively easy to construct and can be made in different designs and dimensions to fit its intended purpose i.e. they can range from a laboratory scale to a very large industrial mill for the continuous processing of tonnes of material at a time. The process can be sealed so pollution from the mill is easy to control. In this study two classes of environmental contaminants were investigated. PAH's are common by-products of combustion and are found as contaminants in many soils. The other compounds investigated were the larger aliphatic hydrocarbons. These were chosen as being representative of the evaporated residues from fuel spills or leaks. A laboratory scale centrifugal ball mill with capacity of approximately 200 g was used for the study. The PAH's investigated were naphthalene, anthracene and phenanthrene. The aliphatic hydrocarbons n-eicosane and n-octacosane were used as the model compounds for hydrocarbon residues. Different soil types (scoria, clay soil, silica sand and slag) were spiked with a known amount of these contaminants. The ball milling was done under different milling conditions i.e. with different ball ratio and with different milling duration. In some experiments there was an addition of materials such as a potential free radical trap or metals to investigate the effect on the mechanochemical reaction. The samples were analysed using an ultrasonic extraction method (EPA METHOD 3550C) with GC and GC-MS analysis of the extract for the quantification of the residual contaminant in the soil and identification of possible secondary products and reaction intermediates. It was found that high destruction efficiency was achieved using milling times of between 120 and 150 minutes and high ball to soil ratios for example 7:1 ball mass to soil mass ratio. Also it was found that different type of soil had an influence on the mechanochemical reaction. A silica matrix was found to have a better destruction rate compared to scoria and clay soil. It was also found that the PAH compounds were more rapidly destroyed by ball milling than were aliphatic hydrocarbons. The addition of BHT was found to reduce destruction rate of both PAH's and aliphatic hydrocarbons. This suggests the mechanism of destruction may involve a free radical mechanism. Aluminium metal was observed to have no significant effect in the destruction. The presence of lubricants such as waxes in the contaminated soil appeared to inhibit the mechanochemical reaction although the mechanism is still uncertain. From this study it was concluded that, the ball mill has considerable potential as an effective, low cost method for the destruction of certain environmental contaminants.

Typewritten copy / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1955

Thesis (M. Phil.)--University of Hong Kong, 2007. / Also available online.

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Oxygen has been shown to be an effective addition of enhancing the bioremediation of petroleum hydrocarbon contamination in porous media; however, the ability to effectively deliver oxygen to petroleum hydrocarbon contaminated groundwater has proven difficult. A field and numerical modelling study was completed at a former gas station in southern Ontario, to assess the delivery of oxygen into groundwater in a fractured limestone aquifer that had been contaminated with petroleum hydrocarbons. A field investigation was completed to characterize the bedrock aquifer and the groundwater flow system. Several hydraulically active fracture zones were identified and characterized. To evaluate how dissolved oxygen would behave in this type of groundwater environment, an injection test was completed using iTi’s gPro® oxygen injection technology. About 1000 L of water containing dissolved oxygen at ~ 30 mg/L and a bromide tracer was injected over ~ 90 minutes and monitored for ~ 10 days in the injection well and in a multilevel monitoring well located 3 metres down-gradient. The oxygen concentration rose rapidly within the injection well and at two of the down-gradient monitor intervals which were aligned with the injection well via major fractures. Concentration tailing persisted in the injection well for several days following injection. The effects of biodegradation were not assessed as part of this investigation. A three-dimensional numerical model for groundwater flow and advective-dispersive transport within a discretely-fractured porous medium was calibrated to the field conditions. The simulated injection test demonstrated that oxygen rapidly filled the porous matrix surrounding the injection well and filled the local intersecting fractures. Following injection, the oxygenated groundwater in the local fractures was rapidly flushed by the natural groundwater flow, with oxygen arrivals appearing as sharp pulses in the fracture-associated breakthrough curves in the monitor well. Back diffusion of oxygen from the porous matrix into the injection well was accurately reproduced by the model. Media properties (fracture apertures, hydraulic gradient and hydraulic conductivity) were varied to assess the sensitivity of the model and to evaluate the effectiveness of the remediation technology under different conditions. The sensitivity runs demonstrated that the distribution of oxygen within the system could be significantly different with varying degrees of advective transport within the fractures and diffusion into the rock matrix which depends on the physical properties and hydrogeological conditions. Predictive simulations were then run with two different injection scenarios: a continuous injection for 1 week and a cyclic injection scenario (injection every 2 days). The same mass of oxygen was delivered in each simulation (~3 kg). The results demonstrated that the delivery of oxygen into the system (continuous or cyclic) could affect the advective transport of oxygen through the fractures and the diffusion of oxygen into the matrix. The continuous injection resulted in a maximum zone of influence (down-gradient and in the transverse direction) while maintaining high levels of oxygen within the matrix. On the other hand the cycle injection provided a more continuous supply of oxygen over time to the system. The zone of influence was reduced but diffusion into the matrix along the fractures increased, creating a more uniform zone of increased oxygen concentrations around the injection well and along the fractures. This study demonstrated that oxygen could effectively be delivered to a fractured bedrock system at levels potentially sufficient to enhance aerobic biodegradation. Additional areas requiring investigation include the behavior of oxygen during hydrocarbon biodegradation through field and modelling studies. Full scale implementation of the technology should then be considered to provide additional information with respect to the applicability of the technology to real world environments.